Yes, you do get infravision with this illusion, if you're a race that didn't already have it (barbarians, humans, erudites). If you're a dark elf you'll have infravison instrad of ultravision with this illusion on.
Doesn't killing froggies in Seb raise faction? I am ally in guk now so i figure it must cuz I was once kos from my younger days and didnt do too much killing in undead Guk.